Brian Brown, president of the National Organization for Marriage, argued that all 31 states that have put same-sex marriage on the ballot voted to ban it.

He told the Washington Post: “We’ve seen these biased polls time and time again – right before votes in which same-sex marriage is rejected. It’s absurd. The people of this country have not changed their opinion about marriage.”

Five states – Massachusetts, Connecticut, Iowa, New Hampshire, Vermont and Washington DC – currently allow gay couples to marry.

California’s ban is under review. Maryland was expected to be next to make the change but a bill failed to gain the necessary support.

In the US, the Defense of Marriage Act bars the federal government from recognising gay marriage. The Obama administration recently announced it would no longer defend the law in court, although the Republican-controlled House has voted to do so.

Democrats in the both the House and the Senate will launch bills to repeal the law shortly.